JELEVA Meglena

This thesis deals with the implementation of prevention actions financed by an insurance company. It is composed of five chapters preceded by a general introduction which aims to present the difficulties linked to prevention, the tools used and the main results obtained. Chapter 1 proposes a method of unsupervised classification of health insurance policyholders into homogeneous risk groups, based on the benefits paid by an insurance company. This method has two phases: first, a dimension reduction of the data using positive matrix factorizations (PMF) is performed. The classification is then finalized using Kohonen maps. The tests of the method are also presented. The final classes obtained are finally analyzed in order to study whether some of them can be the object of a prevention action. A prevention action on psychiatry is proposed. Chapter 2 is a continuation of Chapter 1 since it focuses on comparing the quality of dimension reduction using NMF methods with that obtained using two other methods, the Word2Vec (W2V) and the marginalized stacked debugger autoencoders (mSDA). In particular, the stability of the final classifications is studied using a new stability measure. A complement on the consideration of temporality with the W2V algorithm is also presented. Chapter 3 proposes a study of the psychiatric risk within a complementary health organization, the algorithms of the previous chapters having allowed to identify this risk. With the help of a statistical study conducted on four databases, it is notably shown that insureds using psychiatry cost on average twice as much to the health insurer as an average individual. Some potential preventive actions are suggested in the conclusion. Chapter 4 focuses on the modelling of prevention within an insurance company. By integrating a prevention parameter into the compound Poisson model derived from the theory of ruin, it is indeed possible to measure the effect of prevention on certain indicators, such as the probability of ruin. Different optimal prevention strategies are proposed, and a sensitivity analysis is provided. Finally, chapter 5 proposes to extend the model considered in the previous chapter to the case where an insurance company is confronted with a light risk and a heavy risk. In such a model, the optimal prevention strategy depends on the amounts of reserves built up. Asymptotic results on the optimal strategies are provided.

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This thesis contributes to the understanding of human capital investment decisions of young adults in France. Young adults are in a decisive period in terms of their development and expression of preferences. Particular attention is paid to preferences, as well as to the resulting inequalities. The first chapter focuses on the roles of anticipatory treatment and multivariate preferences in the health insurance decision. Predictions from a theoretical model are tested on data collected in an experimental laboratory. Results show that higher health preference leads to more intensive treatment demand and that being correlation averse leads to more than full coverage. In the second chapter, using survey data, it is shown that differences in the use of care are primarily associated with need, followed by circumstances, reflecting inequalities of opportunity, and effort, reflecting fair inequalities. The third chapter focuses on the effect of students' psychological fragilities on their control beliefs. The instrumental variable strategy shows that more psychological frailties lead to increased control beliefs, which is consistent with the psychological literature that depressed and anxious individuals blame themselves more.

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This thesis deals with the consequences of ambiguity aversion in dynamic contexts in economics. In particular, it focuses on the consequences of ambiguity aversion in irreversible investment decisions, as well as in a dynamic moral hazard problem, modeled in continuous time. The first chapter provides a review of the literature on ambiguity aversion in a dynamic context. We review the existing models and their applications in economics and finance. The second chapter focuses on the irreversible investment decisions of a monopoly and of firms in perfect competition, in the presence of ambiguity about the volatility of the stochastic process governing demand. This particular notion of ambiguity requires the use of recent tools from the theory of nonlinear expectations. We show that in the presence of ambiguity aversion, the optimal strategy of a monopoly implies investing faster than in a perfectly competitive market. The third chapter builds on the results of the second chapter to treat the case of imperfect competition between two firms. The fourth chapter deals with a dynamic moral hazard problem in continuous time and introduces the more classical notion of ambiguity about the drift of the process governing uncertainty. We show that under certain restrictions similar to the standard case, the optimal contract is linear with respect to the final output. This result then allows us to discuss the effect of ambiguity aversion on incentives and the use of information.

The precautionary principle has emerged as a leading guide to public decision-making about environmental risks under irreversibility and uncertainty. In this paper, we adopt a two-period model with irreversibility and agents differentiated by their degree of optimism to character-ize the conditions under which the precautionary principle applies. We show in particular that it is more often applied if the decision-maker has an intermediate optimism index, if scientific research is more effective at reducing uncertainty, and if the same decision-maker makes the decisions for both periods. Moreover, we show that socially optimal decisions lead to apply the precautionary principle more often than an elected decision-maker does.

Dawsonera's home screen says: "How do companies set the volume of their production? What are the determinants of consumer choice? At what level is the price of a good fixed on a market? Why do monopolies form in certain sectors? How does a company react to an offensive action by one of its competitors? This textbook combines theory and practice, emphasizing the acquisition of methods and skills that are essential for any student to succeed in his or her degree.it offers:- concrete situations to introduce the concepts;- a visual course illustrated by numerous examples to assimilate the fundamental knowledge.- interviews to understand how the tools of economic analysis are translated into business strategies - numerous in-depth studies in the book and on www.dunod.com - progressive and varied exercises (MCQs, exercises, problems, exam subjects) to evaluate and train. The detailed answers to the exercises and the in-depth studies are available on www.dunod.com.

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This thesis examines the value of information in the sustainable housing market, combining theoretical, empirical and experimental approaches. First, the perception of the Diagnostic de Performance Énergétique is studied through a survey on a representative sample of the French population. We highlight a nuanced cognitive effectiveness of the label. A part of the population is unaware of it, but attentive subjects use the label to revise their beliefs about energy quality. Second, we provide evidence of the capitalization of this information in real estate prices in two French regions. Low-energy houses present, ceteris paribus, a significant green premium that corresponds to the technical-economic estimates of the associated renovation costs. Despite this 'green value', the pace of energy renovations remains slow on the French market: the information conveyed by the energy label does not reduce the uncertainty on the results of renovation operations. Third, we show through a strategic options model that this uncertainty can delay investment decisions, or even prevent their diffusion. Fourth, we study through a laboratory experiment the willingness of individuals to pay for information, showing that it could largely exceed its theoretical prediction. Nevertheless, the positive effects of paid information could be annihilated by several cognitive biases, requiring a regulation of information markets.

The objective of this thesis is to analyze the interactions between economic agents operating in the retail insurance market. On the one hand, policyholders wishing to cover themselves against a risk of loss must explore the market in order to subscribe to a contract in line with their perception of the risk. On the other hand, insurers compete in a regulated market, imposing on them a certain level of capital in order to guarantee their solvency in a context of uncertainty about the risks underwritten. On the other hand, intermediaries offer their services in order to facilitate the interaction between consumers, who are averse to risk, and firms, which take risks. It is therefore in this context that we analyze the behavior of insurance actors from different perspectives. Chapters 1 and 2 of this thesis are the result of laboratory experiments, carried out using a web interface designed specifically for these studies. The results in Chapter 3 are based on a theoretical model and numerical simulations. Chapter 1 focuses on the relationship between honesty and honesty beliefs of economic agents. Using data collected in the laboratory, we show how uncertainty and the feeling of being in more or less advantageous conditions impact both the level of honesty and the belief in honesty towards others. In general, consumers overestimate the honesty of intermediaries. Thus, this result justifies their presence in the insurance market. On the other hand, we also show that the financial incentives offered to intermediaries distort honesty beliefs. The lower the incentive level, the more dishonest behavior is anticipated by consumers. In Chapter 2, we highlight the dilemma faced by the consumer in a market with multiple distribution channels. Should he explore by himself and choose among a large set of contracts or delegate part of his decision to an intermediary plus or minus search costs, we show that obfuscation related to a large amount of information and beliefs in the honesty of intermediaries are the main determinants of search and purchase decisions. We also show that obfuscation and intermediaries' attitudes are sources of inefficiency in decision making, in particular with respect to the characteristics of the insurance contracts purchased by consumers. In this sense, the identification of a focus effect supports the importance of the price level in decision making to the detriment of the risk environment and the level of coverage. The introduction of search costs in the exploration process, as well as the heterogeneity of honesty beliefs, justify the multi-channel distribution strategies adopted by insurers. An analysis of a repeated non-cooperative game is presented in Chapter 3 of this thesis where losses and consumer behavior are stochastic and insurers compete on price. In order to incorporate the regulators' constraints, we determine Nash equilibria under solvency constraints. We also analyze the sensitivity of equilibrium premiums to the parameters of the game, in particular when firms do not benefit from the same comparative advantages (i.e. reputation leading to different levels of customer retention, insurers' seniority leading to different capital stocks).

In most concrete choice situations, decision-makers cannot predict the outcome of their action with certainty. Decision theory generally distinguishes between the typical case of risk, where the probabilities of different events are objectively known, and the situation of ambiguity, where the informational context does not allow for such objective probabilities.However, agents often hold partial information in the form of sets of past observations, leading to situations that go beyond the traditional dichotomy between known and unknown probabilities.This dissertation provides an empirical analysis of decision behaviors under uncertainty when statistical information is available. The first two chapters focus on choice behavior in the presence of information, i.e., when different options are described by ex ante data sets. These chapters study the influence of the accuracy of information on the perception of ambiguity and on attitudes towards risk and ambiguity.In the third chapter, I consider the case in which agents are not informed and have the opportunity to acquire information. In the third chapter, I consider the case in which agents are uninformed and have the opportunity to acquire information. This chapter proposes an experiment whose objective is to study the way individuals evaluate additional information.

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We propose a review of the recent literature focusing on the effects of ambiguity (or unprobabilized uncertainty) on the behavior of actors in financial markets and on the functioning of these markets. We present theoretical mechanisms of portfolio choice and asset price formation that differ from those based on standard utility expectation models. We also provide a review of empirical and experimental results that illustrate or even support the theoretical predictions described.

The objective of this thesis is to reflect on the systems of coverage of the risks of natural disasters, with particular emphasis on the perception that economic agents have of the characteristics of these risks. The aim is to better understand the determinants of existing coverage systems in the world and of individual behavior, and to compare the different forms of public intervention in the face of these risks. Our work, which is essentially empirical, is based on statistical data from international organizations and risk research centers, but also on behavioral data from a controlled experiment. The typology of flood risk insurance systems in the world that we develop shows that the public system is globally dominant and mainly applied in low-income countries with high exposure to risk, while the mixed public/private system is mainly applied in rich countries with relatively low exposure. Regarding the demand for insurance, the willingness to pay for insurance against natural hazards is significantly lower than that for other hazards, regardless of the probability and amount of loss. By comparing different systems of public intervention, we show that the most effective measure seems to be a subsidy of the insurance premium, but that this can be very costly if the population is predominantly composed of individuals with strong biases in risk perception.

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We propose a review of the recent literature focusing on the effects of ambiguity (or unprobabilized uncertainty) on the behavior of actors in financial markets and on the functioning of these markets. We present theoretical mechanisms of portfolio choice and asset price formation that differ from those based on standard utility expectation models. We also provide a review of empirical and experimental results that illustrate or even support the theoretical predictions described.

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The back cover states: "How do companies determine the volume of their production? What are the determinants of consumer choice? At what level is the price of a good set in a market? Why do monopolies form in certain sectors? How does a company react to an offensive action by one of its competitors? Combining theory and practice, this manual emphasizes the acquisition of methods and skills that are essential for any student to succeed in his or her degree. It offers: concrete situations to introduce the concepts . a visual course illustrated by numerous examples to assimilate the fundamental knowledge of microeconomics . insights into the major authors and current controversies in the discipline . interviews to understand how the tools of economic analysis are translated into corporate strategies . progressive and varied exercises (MCQs, exercises, problems, exam subjects) to evaluate and practice. Detailed answers to the exercises and in-depth studies are available on www.dunod.com.".

We propose a review of the recent literature focusing on the effects of ambiguity (or unprobabilized uncertainty) on the behavior of actors in financial markets and on the functioning of these markets. We present theoretical mechanisms of portfolio choice and asset price formation that differ from those based on standard utility expectation models. We also provide a review of empirical and experimental results that illustrate or even support the theoretical predictions described.

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Many people consider that since the development of curative medicine, prevention has occupied a secondary place in the French health system. Until then, the main concern was to ensure access to care rather than to promote a culture of prevention. In recent years, various health tragedies (blood transfusions, asbestos, heat waves, growth hormone, influenza epidemics, cancers, etc.) have raised public awareness of the concept of "health security" and have led to a new awareness of the problems of prevention. The use of prevention allows individuals and public authorities to exercise control over the health risks to which they are exposed and to carry out consequent actions with the aim of improving the state of health by avoiding the onset, development or aggravation of diseases or accidents, while encouraging individual and collective behaviors that can contribute to reducing health risks. One of the responses to health risks is to encourage individuals to be more preventive, because they are no longer just consumers of care but also producers of their own health. What is therefore the role of individuals and what is their share of responsibility in the prevention of health risks? Moreover, the prevention of health risks is part of an environment of ambiguity and uncertainty because the risks to which individuals are exposed are diverse and not always well known. It is therefore not easy to link a risk factor and a health effect with certainty in order to adopt appropriate preventive behaviour. In this context of uncertainty, many models of decision support, or representations of preferences have been proposed in recent years (Klibanoff et al.(2005), Bleichrodt and Eeckhoudt(2006) Machina(2009), Etner et al.(2011)). This thesis analyzes the prevention behaviors of individuals in the face of health risks while focusing on the proposed public prevention policies. It consists on the one hand of theoretical studies of prevention and health risk management behaviors using recent preference models. This work analyzes the behavior of individuals who must take preventive measures to protect their own health in a context of uncertainty. On the other hand, it is devoted to an empirical study to identify the perceptions and information that individuals have in terms of health risk. In addition, throughout this work, we have sought to study the relevance of the theoretical model developed with regard to the policies practiced. The first chapter presents the principles for modelling economic decisions in the presence of a more or less well known health risk. After detailing the different approaches in models of decisions under risk and uncertainty, we highlight the importance of introducing two-dimensional (or multidimensional) variables into the choice model to allow for the multidimensional environment of health risks. The second chapter is an original study proposed on the analysis of health prevention when individuals are ambiguity averse. In this chapter, we studied individual prevention behaviors in the face of health status uncertainty and showed that ambiguity aversion induces individuals to do more primary and secondary prevention under the assumption of increasing marginal utility of wealth with health status. (.).

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The central objective of this thesis is to study the tax evasion behavior of taxpayers when they report only a portion of their income. The first chapter complements the existing literature by studying the level of income reporting and the effects of changes in tax rates, penalty rates, and control probabilities, by considering nonlinear tax and penalty functions, within the framework of utility expectation theory.The framework provided by cumulative prospect theory is then used in the second chapter. The framework provided by cumulative prospect theory is then used in the second chapter. The focus is on the dependence of the taxpayer's decisions on the benchmark income introduced by this theory. The third chapter characterizes the optimal income tax schedule and the control and penalty strategy to be implemented by the state when the taxpayers' evasion behavior verifies the properties of the prospect theory.

This thesis work focuses on the economic conditions necessary for the emergence of a bioenergy filière through torrefied biomass. This research was conducted following two complementary approaches, one normative, focusing on the study of the behavior of the actors in this filière, and the other positive, focusing on the conditions for the existence of the torrefied biomass market. We study the values that the offreur and the requester associate with the economic decision to invest in new energy technologies and to purchase biomass. We measured the demand of the energy sectors afin to confront it with the offre and deduce an exchange price based on the flexibility of the industrialists in their production process and the environmental constraints they are subject to. The thesis consists of three papers (Chapters 2, 3, and 4 in English) and two confidential studies (Chapters 1 and 5 in French). Chapter 1 presents a qualitative field survey conducted at the national level, identificating potential applicants and determining the techno-economic factors that may influence it. Chapter 2 studies the investment and production decision of an ambiguity-averse agent facing market uncertainties such as the number of players and the effet of competition from other fossil fuels on the selling price of its biomass. We observe asymmetric effects of the two uncertainties on the optimal amounts of production and show theoretically and then numerically that ambiguity aversion tends to decrease the optimal levels of investment and production. Chapter 3 presents the model we developed to estimate the penetration of pre-processed biomass in the power generation market as a function of modeled climate and energy policies. We derive the demand function for torrefied biomass. In Chapter 4, we develop a partial equilibrium model of offre from the torrefaction sector and biomass demand from the power and raffinage sectors to estimate an equilibrium trading price of torrefied biomass as a function of the long-run CO2 price. Enfin, this positive approach is complemented by a logistic study presented in Chapter 5 afin determining the optimal supply strategy and size of pretreatment units located in a biomass production basin. The research work carried out allows for the development of recommendations for investors and institutions in charge of bioenergy development.

The economic analysis of civil liability has developed around the idea that this legal tool can ex ante provide incentives to prevent accident risks. In the presence of large-scale technological risks, this literature has notably highlighted the inefficiencies of the limited liability regime. In an effort to protect investors in order to facilitate the inflow of capital necessary for the emergence of modern production activities, this regime may provide sub-optimal incentives to prevent a risk whose damage is not fully internalized. In Chapter 1, we review this literature and highlight the fact that a comparison with analyses conducted in environmental economics is necessary. Such a comparison, opening the analysis to the possibility of induced technological change, has been initiated in a framework of polluting emissions regulation. Our thesis will then show that such a rapprochement is desirable and will bring new results for the economic analysis of large-scale technological risk prevention. Chapter 2 shows that the possibility of technological change makes it possible to relativize the scope of the inefficiencies of limited liability. We highlight the fact that such a liability regime can lead firms to make technological changes that reduce the probability of accidents and better internalize the risk. In addition, the introduction of a tax based on the level of production reinforces the efficiency of this regime. Chapters 3 and 4 extend the analysis to the presence of imperfectly known risks, which may arise in the presence of new technologies. We compare limited and unlimited liability, and show that the latter provides more incentives to seek risk information while having the least impact on technology choice. Finally, Chapter 5 addresses the issue of innovation, when technical progress can change both the cost of prevention and the probability of accidents. We show that the type of innovation and the role of the Regulator are essential: the no-fault liability rule is always preferable to the negligence rule in the presence of a conformist Regulator, but the latter may be preferable in the presence of a proactive Regulator if the technical progress essentially modifies the prevention cost.

The objective of this thesis is to study the insurance behavior of agents whose preferences in an uncertain world are represented by non-additive models that generalize the utility expectation model and allow the separation of the attitude towards wealth from that towards uncertainty. This representation of preferences, together with the assumption that agents do not know precisely the probability distribution of their losses, makes the modeling of insurance behavior more realistic and allows a better understanding of the choices observed in the markets. The first chapter of the thesis is devoted to the presentation of choice models in uncertain probabilistic and non-probabilistic conditions. It is followed by the study of the demand for insurance in the classical framework of a single risk, first when the agent is able to locate the probability distribution of his losses within a set of given distributions and his preferences are represented by the Jaffray model, then when he is in a general framework of non-probabilized uncertainty and his preferences are represented by the utility expectation à la Choquet. In the third chapter, we extend the scope of the study by considering the demand for insurance in the presence of an additional, uninsurable risk. The impact of this additional risk on the demand for insurance is studied in the case where the two risks are comonotone and anti-comonotone. We then focus on the supply behavior of an insurer in an anti-selection model, when the information of the insureds on their loss probabilities is imprecise. The last chapter of the thesis is devoted to an empirical study of the determinants of the purchase of life insurance contracts, with the objective of testing the impact of agents' beliefs on their actual choice of insurance contracts.